Organic light emitting device and method for manufacturing the same

ABSTRACT

Disclosed is an organic light emitting device (OLED) that may include a first electrode including at least two conductive units that are immediately adjacent to each other; a second electrode facing the first electrode; an organic layer between the first electrode and the second electrode; and an auxiliary electrode electrically connected to the first electrode, the auxiliary electrode including at least two branch points that are immediately adjacent to each other, each branch point having at least three branches, wherein a resistance between the at least two branch points is 35Ω or less, and wherein a resistance between the at least two conductive units is 2,000Ω or more and 600,000Ω or less.

This application is a Continuation Bypass of International ApplicationNo. PCT/KR2014/003066, filed Apr. 9, 2014, and claims the benefit ofKorean Application No. 10-2013-0047429, filed on Apr. 29, 2013, all ofwhich are hereby incorporated by reference in their entirety for allpurposes as if fully set forth herein.

TECHNICAL FIELD

The present specification relates to an organic light emitting device(OLED) and a method for manufacturing the OLED.

BACKGROUND ART

An organic light emitting phenomenon refers to a phenomenon ofconverting electrical energy to light energy using an organic material.That is, when positioning an appropriate organic layer between an anodeand a cathode, and then applying a voltage between two electrodes, holesare injected into the organic layer from the anode and electrons areinjected into the organic layer from the cathode. Excitons are generatedwhen the injected holes and electrons encounter each other, and light isgenerated when the excitons fall down to a lower energy state.

Since an interval between the anode and the cathode is small, an organiclight emitting device (OLED) is easy to have a short-circuit defect. Dueto a pinhole, a crack, a step and coating roughness in a structure ofthe OLED, and the like, the anode and the cathode may directly contactwith each other. The thickness of the organic layer may become thinnerin such a defect zone. The defect zone may provide a low resistance pathin which current easily flows, thereby reducing or preventing sufficientcurrent from flowing through the OLED in an extreme case. Accordingly,light emitting output of the OLED may decrease or disappear.

In a multi-pixel OLED, such a short-circuit defect may generate a deadpixel of not emitting light or emitting light less than the averagelight intensity, thereby degrading the display quality. In the case of alighting or other low resolution usages, a large portion of the OLEDdevice may not operate due to the short-circuit defect.

Due to concerns about the short-circuit defect, manufacturing of an OLEDis generally performed in a clean room. However, even a cleanenvironment may not effectively remove the short-circuit defect. In manycases, to decrease the number of short-circuit defects by increasing theinterval between two electrodes, the thickness of the organic layer maybe unnecessarily increased as compared to a thickness desired to operatethe OLED. Such a method may add cost in manufacturing the OLED. Further,the method may not completely remove the short-circuit defect.

SUMMARY OF THE INVENTION

The present invention is to provide an organic light emitting device(OLED) that may operate within a normal range even in a case in which afactor capable of causing a short-circuit defect is present, that is,even in a case in which the short-circuit defect occurs, and a methodfor manufacturing the OLED.

The present invention is to provide an OLED that may reduce or preventlight intensity of a peripheral area from being degraded due to avoltage drop (IR drop) of a short-circuit occurrence area in a case inwhich a short-circuit defect occurs, and a method for manufacturing theOLED.

An exemplary embodiment of the present specification is to provide anOLED, including: a first electrode; a second electrode provided to facethe first electrode; at least one organic layer provided between thefirst electrode and the second electrode; and an auxiliary electrodeelectrically connected to the first electrode,

wherein the first electrode includes at least two conductive units, andresistance between the different conductive units is 2,000Ω or more and600,000Ω or less, and

the auxiliary electrode includes at least two branch points each havingat least three branches, and resistance between the adjacent branchpoints is 35Ω or less.

The OLED according to an exemplary embodiment of the presentspecification may further include a short-circuit preventing portionprovided between the conductive unit and the auxiliary electrode, andeach conductive unit may be supplied with current through theshort-circuit preventing portion.

In the OLED according to an exemplary embodiment of the presentspecification, the first electrode may further include at least twoconductive connectors each including an area in which a length of adirection in which current flows is longer than a width of a verticaldirection thereof, one end portion of each conductive connector may beelectrically connected to the conductive unit, and another end portionthereof may be electrically connected to the auxiliary electrode.

The OLED according to an exemplary embodiment of the presentspecification may further include a short-circuit preventing layerprovided between the first electrode and the auxiliary electrode, andthe auxiliary electrode may be electrically connected to the conductiveunits through the short-circuit preventing layer.

Another exemplary embodiment of the present specification provides amethod for manufacturing the OLED. Specifically, provided is the methodfor manufacturing the OLED, the method including: preparing a substrate;forming a first electrode including at least two conductive units on thesubstrate; forming an auxiliary electrode disposed to be separate fromthe conductive units and at least two branch points each having at leastthree branches; forming at least one organic layer on the firstelectrode; and forming a second electrode on the organic layer.

Still another exemplary embodiment of the present specification providesa display device including the OLED.

Still another exemplary embodiment of the present specification providesa lighting device including the OLED.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

An OLED of the present specification may normally maintain a function ofthe OLED even though a short circuit occurs due to a defect of asubstrate itself.

An OLED of the present specification may stably operate withoutincreasing a leakage current amount even when an area size of ashort-circuit occurrence point increases.

An OLED of the present specification may reduce or prevent a decrease inluminescence intensity around an area in which a short-circuit defectoccurs.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. These andother advantages of the invention will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIGS. 1 and 2 illustrate an example of a patterned first electrodeaccording to an exemplary embodiment of the present specification.

FIG. 3 illustrates an example of a length and a width in a conductiveconnector of the present specification.

FIGS. 4 and 5 illustrate an example of a configuration in which anauxiliary electrode surrounds a conductive unit according to anexemplary embodiment of the present specification.

FIG. 6 illustrates an example in a case in which a short circuit occursin a striped auxiliary electrode and in a case in which the shortcircuit occurs in an auxiliary electrode having at least two branchpoints according to an example of the present specification.

FIG. 7 illustrates an example of resistance between adjacent branchpoints of an auxiliary electrode according to an exemplary embodiment ofthe present specification.

FIG. 8 illustrates a partial area of a state in which a first electrodeand an auxiliary electrode are formed during a manufacturing process ofan OLED manufactured according to an Example and a Comparative Exampleof the present specification.

FIG. 9 illustrates a state after causing a short-circuit defect to anOLED manufactured according to the Example of the present specificationand the Comparative Example.

FIG. 10 illustrates potential of an auxiliary electrode per position ina case in which a short circuit has not occurred in an OLED according toa Comparative Example.

FIG. 11 illustrates potential of an auxiliary electrode per position ina case in which a short circuit has occurred in an OLED according to aComparative Example.

FIG. 12 illustrates a driving characteristic of an OLED according to thepresent specification.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. The same reference numbers may be used throughout the drawingsto refer to the same or like parts.

In the following description, when a predetermined member is positioned“on” another member, it may include not only a case in which thepredetermined member contacts with the other member but also a case inwhich other additional member(s) is present between the two members.

An exemplary embodiment of the present specification provides an organiclight emitting device (OLED), including: a first electrode; a secondelectrode provided to face the first electrode; at least one organiclayer provided between the first electrode and the second electrode; andan auxiliary electrode electrically connected to the first electrode.

The first electrode includes at least two conductive units, and aresistance between the different conductive units is 2,000Ω or more and600,000Ω or less.

The auxiliary electrode includes at least two branch points, with eachhaving at least three branches, and a resistance between the adjacentbranch points is 35Ω or less.

Current may be supplied to each conductive unit of the presentspecification through an area having as a short-circuit preventingfunction. Specifically, according to an exemplary embodiment of thepresent specification, the OLED may include a short-circuit preventingportion provided between the conductive unit and the auxiliaryelectrode, and the conductive unit and the auxiliary electrode may beelectrically connected through the short-circuit preventing portion.

According to an exemplary embodiment of the present specification, theshort-circuit preventing portion may be a conductive connector or ashort-circuit preventing layer, or may include the conductive connectorand the short-circuit preventing layer.

According to an exemplary embodiment of the present specification, atcurrent density of any one value of 1 mA/cm² to 5 mA/cm², theshort-circuit preventing portion may have a resistance value at which anoperating voltage increase rate of the following Formula 1 and anumerical value of operating current to leakage current of the followingFormula 2 simultaneously satisfy 0.03 or less:

$\begin{matrix}\frac{V_{t} - V_{o}}{V_{o}} & \left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack \\\frac{I_{s}}{I_{t}} & \left\lbrack {{Formula}\mspace{14mu} 2} \right\rbrack\end{matrix}$

wherein V_(t)(V) denotes operating voltage of the OLED to which theshort-circuit preventing portion is applied and in which a short circuitdefect is absent,

V_(o)(V) denotes operating voltage of the OLED to which theshort-circuit preventing portion is not applied and in which theshort-circuit defect is absent,

I_(t)(mA) denotes operating current of the OLED to which theshort-circuit preventing portion is applied and in which theshort-circuit defect is absent, and

I_(s)(mA) denotes leakage current of the OLED to which the short-circuitpreventing portion is applied and in which the short-circuit defect ispresent in any one conductive unit.

V_(o)(V) may denote operating voltage in a case in which theshort-circuit defect is absent in an OLED of which a remainingconfiguration excluding only the short-circuit preventing portion is thesame.

Resistance or a resistance value of the short-circuit preventing portionmay denote resistance from one end portion of the short-circuitpreventing portion to the other end portion thereof. Specifically, theresistance or the resistance value of the short-circuit preventingportion may be resistance from the conductive unit to the auxiliaryelectrode.

A process of inducing the resistance value of the short-circuitpreventing portion at which the operating voltage increase rate of theabove Formula 1 and the numerical value of operating current to leakagecurrent of the above Formula 2 simultaneously satisfy 0.03 or less is asfollows.

In a state in which the short circuit defect is absent, the operatingcurrent I_(t)(mA) of the OLED may be expressed as the following formula.I _(t) =n _(cell) ×I _(cell)

n_(cell) denotes the number of conductive units corresponding to a lightemitting area in the OLED.

I_(cell) denotes current (mA) operating in one conductive unit in a casein which the OLED normally operates.

Each conductive unit is connected in parallel and thus, resistance(R_(org))(Ω) applied to the entire OLED may be expressed as follows.

$R_{org} = \frac{R_{{cell} - {org}}}{n_{cell}}$

R_(cell-org)(Ω) denotes organic resistance (Ω) in one conductive unit.

Compared to a case in which the short-circuit preventing portion isabsent, operating voltage increases in the OLED including theshort-circuit preventing portion. Accordingly, when the short-circuitpreventing portion is applied, the short-circuit preventing portion isdesigned such that the efficiency of the OLED is not greatly degraded.

In a normal operation state of the OLED, the operating voltage increaserate occurring when the short-circuit preventing portion is added may beexpressed as the following Formula 1.

$\begin{matrix}\frac{V_{t} - V_{o}}{V_{o}} & \left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In the above Formula 1, V_(t)(V) denotes operating voltage of the OLEDto which the short-circuit preventing portion is applied and in whichthe short circuit defect is absent and V_(o)(V) denotes operatingvoltage of the OLED to which the short-circuit preventing portion is notapplied and in which the short circuit defect is absent.

The operating voltage increase rate ((V_(t)−V_(o))/V_(o)) may becalculated according to the following formula.

$\frac{V_{t} - V_{o}}{V_{o}} = \frac{R_{{cell} - {spl}}}{n_{{cell} - {org}}}$

R_(cell-spl) denotes resistance (Ω) of the short-circuit preventingportion in one conductive unit.

R_(cell-org) denotes organic resistance (Ω) in one conductive unit.

The operating voltage increase rate ((V_(t)−V_(o))/V_(o)) may be inducedthrough the following formula.

$V_{o} = \frac{I_{t} \times \left( R_{org} \right)}{1000}$$V_{t} = {I_{cell} \times \frac{\left( {R_{{cell} - {org}} + R_{{cell} - {spl}}} \right)}{1000}}$

In the case of the OLED in which the short-circuit preventing portion isabsent, when defining, as I_(n), current (mA) flowing through a normalorganic layer in the case of the short-circuit occurrence, defining, asI_(s), leakage current (mA) flowing into a short-circuit occurrencepoint, and defining, as R_(org-s), organic resistance (Ω) of theshort-circuit occurrence point, I_(n) and I_(s) may be expressed asfollows.

$\mspace{79mu}{I_{n} = {\frac{V_{0}}{R_{org}} = {{I_{t} \times \frac{R_{org} \times R_{{org} - s}}{R_{org} + R_{{org} - s}} \times \frac{1}{R_{org}}} = 0}}}$$I_{s} = {\frac{V_{0\;}}{R_{{org} - s}} = {{I_{t} \times \frac{R_{org} \times R_{{org} - s}}{R_{org} + R_{{org} - s}} \times \frac{1}{R_{{org} - s}}} = {{I_{t} \times \frac{R_{org}}{R_{org} + R_{{org} - s}}} = I_{t}}}}$

That is, in a case in which the short circuit occurs in a partial areaof the OLED in which the short circuit-preventing portion is absent, allthe set current may escape through the short-circuit area (I_(s)) whileR_(org-s), drops to a value close to “0”. Accordingly, in the case ofthe OLED in which the short-circuit preventing portion is absent, if theshort circuit occurs, the current may not flow in the normal organiclayer and thus, the OLED may not emit light.

In the case of the OLED in which the short-circuit preventing portion isprovided, when defining I_(n-cell) as current (mA) flowing through anormal light emitting area in the case of the short-circuit occurrence,voltage of each parallel-connected conductive unit is identical and asum of currents of all of the parallel-connected conductive units isidentical to operating current (I_(t)) of the OLED. It may be verifiedfrom the following formula.(R _(cell-org) +R _(cell-spl))×I _(n-cell)=(R _(cell-s) +R_(cell-spl))×I _(s)I _(t) =I _(n-cell)×(n _(cell)−1)+I _(s)

Also, in the case of the OLED in which the short-circuit preventingportion is provided, the leakage current flowing into the short-circuitoccurrence point may be calculated as follows.

$I_{s} = {I_{t} \times \frac{\left( {R_{{cell} - {org}} + R_{{cell} - {spl}}} \right)}{\left( {R_{{cell} - {org}} + R_{{c\;{ell}} - {spl}}} \right) + {\left( {n_{cell} - 1} \right) \times \left( {R_{{cell} - s} + R_{{cell} - {spl}}} \right)}}}$

Accordingly, in the OLED according to an exemplary embodiment of thepresent specification in which the short-circuit preventing portion isprovided, even though the organic layer of any one conductive unit isshort circuited (R_(cell-s)=0), it may be possible to significantlydecrease an amount of leakage current when a value of a denominatorsufficiently increases, which can be verified from the above formula.

The numerical value of the operating current (I_(t)) to the leakagecurrent (I_(s)) of the OLED in which the short-circuit preventingportion is provided may be expressed as the following Formula 2.

$\begin{matrix}\frac{I_{s}}{I_{t}} & \left\lbrack {{Formula}\mspace{14mu} 2} \right\rbrack\end{matrix}$

In the above Formula 2, I_(t)(mA) denotes the operating current of theOLED to which the short-circuit preventing portion is applied and inwhich the short-circuit defect is absent, and I_(s)(mA) denotes theleakage current of the OLED to which the short-circuit preventingportion is applied and in which the short-circuit defect is present inany one conductive unit.

Further, the appropriate numerical value range of the operating current(I_(t)) to the leakage current (I_(s)) of the OLED in which theshort-circuit preventing portion is provided may be calculated throughthe following formula.

$\frac{I_{s}}{I_{t}} = \frac{\left( {R_{{cell} - {org}} + R_{{cell} - {spl}}} \right)}{\left( {R_{{cell} - {org}} + R_{{c\;{ell}} - {spl}}} \right) + {\left( {n_{cell} - 1} \right) \times \left( {R_{{cell} - s} + R_{{cell} - {spl}}} \right)}}$

According to an exemplary embodiment of the present specification, theshort-circuit preventing portion may have a resistance value at whichthe operating voltage increase rate ((V_(t)−V_(o))/V_(o)) and thenumerical value of the operating current to the leakage current(I_(s)/I_(t)) of the OLED simultaneously satisfy 0.03 or less. Morespecifically, the short-circuit preventing portion may have a resistancevalue at which the operating voltage increase rate ((V_(t)−V_(o))/V_(o))and the numerical value of the operating current to the leakage current(I_(s)/I_(t)) simultaneously satisfy 0.01 or less.

Specifically, according to an exemplary embodiment of the presentspecification, in the above Formula 1 and the above Formula 2, thecurrent density in the case of operation of the OLED may be any onevalue of 1 mA/cm² to 5 mA/cm².

According to an exemplary embodiment of the present specification,resistance between one conductive unit and another conductive unit maybe 2,000Ω or more and 600,000Ω or less. Specifically, the resistancevalue indicates resistance from the one conductive unit to the otherconductive unit through the short-circuit preventing portion if itexists. That is, that the resistance between the different conductiveunits is 2,000Ω or more and 600,000Ω or less indicates that eachconductive unit is electrically connected to the short-circuitpreventing portion and thereby is supplied with the current. Theresistance between one conductive unit and another conductive unitadjacent to each other can be measured by probing substantially centerpoints of the two conductive units.

The conductive unit according to an exemplary embodiment of the presentspecification may be included in a light emitting area of the OLED.Specifically, according to an exemplary embodiment of the presentspecification, at least an area of each conductive unit may bepositioned on the light emitting area of the OLED. That is, according toan exemplary embodiment of the present specification, a light emittingphenomenon may occur on an organic layer including a light emittinglayer formed on an area that constitutes the conductive unit, and lightmay be emitted through the conductive unit.

According to an exemplary embodiment of the present specification, thecurrent of the OLED may flow in the auxiliary electrode, theshort-circuit preventing layer, the conductive unit, the organic layer,and the second electrode, and may flow in a reverse direction thereof.Alternatively, the current of the OLED may flow in the auxiliaryelectrode, the conductive connector, the conductive unit, the organiclayer, and the second electrode, and may flow in a reverse directionthereof. Alternatively, the current of the OLED may flow in theauxiliary electrode, the short-circuit preventing layer, the conductiveconnector, the conductive unit, the organic layer, and the secondelectrode, and may flow in a reverse direction thereof.

According to an exemplary embodiment of the present specification, eachconductive unit may be supplied with current from the auxiliaryelectrode through the short-circuit preventing portion.

The light emitting area indicates an area in which light emitted fromthe light emitting layer of the organic layer is emitted through thefirst electrode and/or the second electrode. For example, in the OLEDaccording to an exemplary embodiment of the present specification, thelight emitting area may be formed on at least a portion of an area ofthe first electrode in which the short-circuit preventing portion and/orthe auxiliary electrode are not formed in an area in which the firstelectrode is formed on the substrate. Also, a non-emitting areaindicates a remaining area excluding the light emitting area.

According to an exemplary embodiment of the present specification, theshort-circuit preventing portion may be positioned on the non-emittingarea of the OLED.

According to an exemplary embodiment of the present specification, eachconductive unit may be electrically connected in parallel. Theconductive units may be disposed to be separate from each other. Aconfiguration in which the conductive units are separate from each othermay be verified from resistance between the conductive units.

Specifically, according to an exemplary embodiment of the presentspecification, resistance from the one conductive unit to anotherconductive unit adjacent thereto may be at least two folds of resistanceof the short-circuit preventing portion. For example, in a case in whicha current carrying path between any one conductive unit and anotherconductive unit adjacent thereto is constituted merely through theshort-circuit preventing portion and the auxiliary electrode, theconductive unit and the other conductive unit adjacent thereto passthrough the auxiliary electrode and the short-circuit preventing portiontwice. Accordingly, even though a resistance value of the auxiliaryelectrode is ignored, the resistance between the conductive units mayhave a resistance value corresponding to at least two folds of theshort-circuit preventing portion.

That is, according to an exemplary embodiment of the presentspecification, resistance from each conductive unit to the auxiliaryelectrode may be 1,000Ω or more and 300,000Ω or less.

According to an exemplary embodiment of the present specification, in acase in which the conductive units are directly electrically connectedto each other instead of being disposed to be separate from each other,a resistance value of the directly connected area may be higher than aresistance value of the short-circuit preventing portion. In this case,even though the conductive units are not disposed to be completelyseparate from each other, it may be possible to maintain a normalshort-circuit preventing function in a case in which a short circuitoccurs.

The conductive units may be separate from each other and therebyelectrically separate from each other. Each conductive unit may besupplied with current from the auxiliary electrode through theshort-circuit preventing portion. This may reduce or prevent the overallnon-operation of the OLED from occurring when current that is to flow inanother conductive unit in which the short circuit is absent flows in aconductive unit in which the short circuit is present, in a case inwhich the short circuit occurs in any one conductive unit.

According to an exemplary embodiment of the present specification, thefirst electrode may further include the conductive connector having theshort-circuit preventing function.

Specifically, according to an exemplary embodiment of the presentspecification, the first electrode may further include at least twoconductive connectors each including area in which a length of adirection in which current flows is longer than a width of a verticaldirection thereof. One end portion of each conductive connector may beelectrically connected to the conductive unit and another end portionthereof may be electrically connected to the auxiliary electrode.

Specifically, according to an exemplary embodiment of the presentspecification, the conductive connector may include an area in which aratio of the length to the width is 10:1 or more.

The conductive connector may be an end portion of the conductive unit inthe first electrode and a shape or a position thereof is notparticularly limited. For example, in a case in which the conductiveunit is formed in a flattened “U” shape or an “L” shape, the conductiveconnector may be an end portion of the conductive unit. Alternatively,the conductive connector may have a shape that is protruded from onevertex, one corner, or a middle portion of one side of the conductiveunit in a polygonal shape such as a rectangular shape.

Alternatively, according to an exemplary embodiment of the presentspecification, the first electrode may further include the conductiveconnector including the short-circuit preventing function and thecurrent carrying portion of the first electrode configured toelectrically connect the conductive connectors. In this case, theauxiliary electrode may be electrically connected to the conductiveconnector through the current carrying portion of the first electrode.Specifically, the auxiliary electrode may be provided on the currentcarrying portion of the first electrode.

According to an exemplary embodiment of the present specification, thecurrent carrying portion of the first electrode or the auxiliaryelectrode may be provided to be separate from the conductive unit.

“On the current carrying portion” may also indicate one side surface ofthe current carrying portion in addition to only a top surface of thecurrent carrying portion. Also, “on the current carrying portion” mayalso indicate one area of a top surface, a bottom surface, or a sidesurface of the current carrying portion. Also, “on the current carryingportion” may also include one area of the top surface of and one area ofthe side surface of the current carrying portion, and may include onearea of the bottom surface and one area of the side surface of thecurrent carrying portion.

The current carrying portion of the first electrode of the presentspecification may function to physically connect each conductiveconnector and to flow current in each conductive unit through eachconductive connector.

The conductive units may be physically connected by the current carryingportion of the first electrode and the conductive connector through apatterning process of the first electrode, and may be electricallyconnected in parallel. An example thereof is illustrated in FIG. 1.

Referring to FIG. 1, a patterned first electrode includes a conductiveunit 1 and a conductive connector 2 and the patterned first electrode isphysically connected to a current carrying portion 4 of the firstelectrode.

Each conductive unit may be supplied with current from the auxiliaryelectrode through the conductive connector. Alternatively, theconductive unit may be supplied with the current through an auxiliaryelectrode and a current carrying portion of the first electrode.

The conductive connector may be patterned in a form of being connectedto each conductive unit through a patterning process of the firstelectrode. An example thereof is illustrated in FIG. 2.

Referring to FIG. 2, the patterned first electrode includes theconductive unit 1 and the conductive connector 2.

The conductive connector may have a relatively high resistance comparedto the conductive unit. Further, the conductive connector may perform ashort-circuit preventing function in the OLED. That is, even when ashort-circuit defect occurs due to a short circuit occurring in theOLED, the conductive connector may function to enable an operation ofthe OLED.

According to an exemplary embodiment of the present specification, amaterial of the conductive connector may be the same as a material ofthe conductive unit. Specifically, the conductive connector and theconductive unit are included in the first electrode and thus, may beformed using the same material.

The short-circuit defect may occur in a case in which the secondelectrode directly contacts with the first electrode. Alternatively, theshort-circuit defect may occur even in a case in which due to a decreasein a thickness or deformation of the organic layer disposed between thefirst electrode and the second electrode, a function of the organiclayer is lost and thereby the first electrode and the second electrodecontact with each other. When the short circuit defect occurs, a lowcurrent path may be provided to the OLED, thereby enabling the OLED toanomalously operate. Due to a leakage current that directly flows fromthe first electrode to the second electrode by the short-circuit defect,current of the OLED may flow avoiding a zero-defect zone. It maydecrease the light emitting output of the OLED. In a serious case, theOLED may not operate. Also, when current distributed and thereby flowingover a wide area of organic materials is concentrated and thereby flowsat a short-circuit occurrence point, high heat may be locally generatedso that the OLED may be broken or a fire may occur.

However, even when the short-circuit defect occurs in any one or moreconductive units among the conductive units of the OLED according to anexemplary embodiment of the present specification, it may be possible toprevent all the driving current from flowing in a short-circuit defectportion using the conductive connector. That is, the conductiveconnector may perform a role of controlling an amount of leakage currentnot to unlimitedly increase. Accordingly, even when the short-circuitdefect occurs in a portion of the conductive units of the OLED,remaining conductive units in which the short-circuit defect is absentmay normally operate.

The conductive connector has a high resistance value. Therefore, in acase in which the short-circuit defect occurs, the conductive connectormay provide an appropriate resistance, thereby reducing or preventingthe current from leaking through the short-circuit defect portion. Tothis end, the conductive connector may have a resistance value suitablefor decreasing the leakage current caused by the short-circuit defectand the light emitting efficiency loss associated therewith.

According to an exemplary embodiment of the present specification, theconductive connector may have a resistance value capable of reducing orpreventing the short-circuit defect by including a portion in which aratio of the length to the width is 10:1 or more. Further, according toan exemplary embodiment of the present specification, the portion inwhich the ratio of the length to the width is 10:1 or more may be anentire area of the conductive connector. Alternatively, the area inwhich the ratio of the length to the width is 10:1 or more may be apartial area of the conductive connector.

The length and the width are relative concepts and thus, the lengthindicates a spatial distance from one end of the conductive connector tothe other end thereof from view of an upper portion. That is, eventhough the conductive connector is a combination of straight lines orincludes a curve, the length indicates a value obtained by measuring thelength based on the assumption that the length is a straight line. Thewidth indicates a distance from a center of a lengthwise direction ofthe conductive connector to both ends of a vertical direction thereoffrom view of an upper portion. Also, when the width varies, it may be anaverage value of a width of any one conductive connector. An example ofthe length and the width is illustrated in FIG. 3.

The length indicates a dimension of a direction in which the currentflows. Also, the width of the present specification indicates adimension of a direction vertical to the direction in which the currentflows.

The length indicates a travel distance of the current from the currentcarrying portion of the first electrode or the auxiliary electrode tothe conductive unit. The width indicates a distance vertical to thelengthwise direction.

In FIG. 3, the length may be a summation of “a” and “b”, and the widthmay be “c”.

According to an exemplary embodiment of the present specification,resistance of the conductive connector may satisfy the following Formula3:(Length of conductive connector÷width of conductive connector)×surfaceresistance of conductive connector≧1,000Ω  [Formula 3]

The length of the conductive connector may be a length from one endportion of the conductive connector to the other end portion thereof asa length of a direction in which current flows in the conductiveconnector. Also, the width of the conductive connector indicates a widthof a direction vertical to the length of the conductive connector andindicates an average value of the width in a case in which the width ofthe conductive connector is not constant.

That is, according to an exemplary embodiment of the presentspecification, the resistance of the conductive connector may be 1,000Ωor more. Specifically, the resistance of the conductive connector may be1,000Ω or more and 300,000Ω or less.

In a case in which the resistance of the conductive connector is withinthe above range, the conductive connector may perform an appropriateshort-circuit preventing function for the occurrence of theshort-circuit defect. That is, in a case in which the resistance of theconductive connector is 1,000Ω or more, it may possible to effectivelyprevent the leakage current from flowing in an area in which theshort-circuit defect is present.

According to an exemplary embodiment of the present specification,resistance from the current carrying portion of the first electrode orthe auxiliary electrode to the conductive unit may be 1,000Ω or more and300,000Ω or less.

According to an exemplary embodiment of the present specification,resistance between different conductive units indicates resistancereaching the one conductive unit and a short-circuit preventing portioncontacting therewith, the auxiliary electrode, a short-circuitpreventing portion contacting with another conductive unit, and theother conductive unit.

According to the above Formula 3, the resistance indicates a lower limitvalue of resistance at which the conductive connector may perform theshort-circuit preventing function in a case in which the conductive unitis supplied with the current through the conductive connector.

The auxiliary electrode according to an exemplary embodiment of thepresent specification may include at least two branch points. Eachbranch point may include at least three branches. The auxiliaryelectrode does not include conductive lines that are not electricallyconnected to each other, and the auxiliary electrode may be provided ina form in which at least two conductive lines partially contact witheach other. That is, the auxiliary electrode is not provided in a stripeshape and may be provided in a form including an area in which at leasttwo conductive lines intersect each other.

The branch point indicates an area in which the auxiliary electrodescontact with each other and thereby form at least three branches.Through the branch points, the current of the auxiliary electrode maydistributedly flow in the branches.

According to an exemplary embodiment of the present specification, theauxiliary electrode may be disposed to be separate from the conductiveunits and provided in a mesh structure of surrounding at least oneconductive unit.

According to an exemplary embodiment of the present specification, theauxiliary electrode may be disposed to be separate from the conductiveunit; and an area excluding the end portion of the conductive connectorin contact with the auxiliary electrode. Specifically, the auxiliaryelectrode may not be provided on an area of performing the short-circuitpreventing function of the conductive connector. That is, the auxiliaryelectrode may need to be separate from an area in which a length of adirection in which the current of the conductive connector flows islonger than a width of a vertical direction thereof. This is because aresistance value decreases and the short-circuit preventing function isdegraded when the auxiliary electrode having a low resistance valuecontacts an area having a high resistance value.

FIGS. 4 and 5 illustrate an example of a configuration in which anauxiliary electrode surrounds a conductive unit according to anexemplary embodiment of the present specification.

Referring to FIGS. 4 and 5, the auxiliary electrode is disposed to beseparate from the conductive unit and is electrically connected to oneend portion of the conductive connector.

In a case in which a short-circuit defect occurs in a local area of theOLED employing a short-circuit preventing function, when the auxiliaryelectrode is provided in a striped shape, a light intensity of aperipheral portion of the local area in which the short-circuit defectoccurs may be decreased. Compared to a normal operation, an amount ofcurrent as much as about 100 folds may flow in the local area in whichthe short-circuit defect occurs, whereby a great voltage drop (IR drop)phenomenon occurs in the auxiliary electrode of the local area in whichthe short-circuit defect occurs. That is, it may be possible to preventthe entire OLED from not operating using the short-circuit preventingfunction. Also, the local area in which the short-circuit defect occursmay become dark and thus, the product quality may be significantlydegraded.

Accordingly, in the OLED according to an exemplary embodiment of thepresent specification, the auxiliary electrode includes at least twobranch points each having at least three branches, thereby enabling thecurrent to be distributed over a wide area in a case in which a shortcircuit occurs. That is, the auxiliary electrode is designed such thatthe voltage drop (IR drop) occurring in the auxiliary electrode of theshort-circuit occurrence area can be reduced or minimized and thus, alight intensity of the OLED may be uniform even when such ashort-circuit defect occurs.

FIG. 6 compares (a) a case in which a short circuit occurs in a stripedauxiliary electrode and (b) a case in which the short circuit occurs inan auxiliary electrode having at least two branch points according to anexemplary embodiment of the present invention. In FIG. 6, X mA indicatesthe leakage current in a case in which a short-circuit occurs.

Referring to FIG. 6, in a case in which a short circuit occurs, theauxiliary electrode has a greater effect in distributing the currentover a wide area compared to the striped auxiliary electrode.

According to an exemplary embodiment of the present specification,resistance between adjacent branch points of the auxiliary electrode maybe 35Ω or less. Specifically, the resistance between the adjacent branchpoints of the auxiliary electrode may be 18Ω or less. Also, theresistance between the adjacent branch points of the presentspecification may be 0Ω or more.

Alternatively, according to an exemplary embodiment of the presentspecification, a distance between the adjacent branch points of theauxiliary electrode may be 21 mm or less. Specifically, the distancebetween the adjacent branch points may be 0.2 mm or more and 21 mm orless.

According to an exemplary embodiment of the present specification, thedistance between the adjacent branch points of the auxiliary electrodemay be 10 mm or less, or may be 0.2 or more and 10 mm or less.

According to an exemplary embodiment of the present specification, thedistance between the adjacent branch points of the auxiliary electrodemay be 10 mm or less and the resistance between the adjacent branchpoints may be 18Ω or less.

In a case in which the resistance between the adjacent branch points ofthe auxiliary electrode and/or the distance between the adjacent branchpoints is within the above range, the distribution of the current may beeasily performed for the short-circuit occurrence and the voltage drop(IR drop) may be minimized. A detailed description related thereto maybe more clearly understood by the following Example and ComparativeExample.

FIG. 7 illustrates an example of resistance between adjacent branchpoints of an auxiliary electrode according to an exemplary embodiment ofthe present specification. Specifically, FIG. 7 illustrates an exampleof adjacent branch points. In a case of measuring a resistance betweenthe adjacent branch points, a measurement is performed in a state inwhich all of the detour-able auxiliary electrodes between the adjacentbranch points are excluded.

The following Example shows that more than 10% of non-uniformity ofluminance, which is caused by a short circuit occurrence, may not occurin an OLED according to an exemplary embodiment of the presentspecification.

The distance between the adjacent branch points of the auxiliaryelectrode of the OLED and the resistance range between the adjacentbranch points will now be described.

FIG. 12 illustrates a driving characteristic of an OLED according to anexemplary embodiment of the present specification. FIG. 12 showsbrightness according to operating voltage of the OLED.

In a case in which the operating voltage of the OLED is 6V, theluminance may be around 3000 nit and a brightness variation of 10% maybe around 2700 nit. Further, an operating voltage difference between3000 nit and 2700 nit is 0.066 V. Also, for the brightness variation of5%, the operating voltage difference is 0.033 V.

According to an exemplary embodiment of the present specification, in acase in which the OLED is short circuited, the voltage drop is desiredto be 0.066V or less in order to achieve the luminance non-uniformitywithin 10% of a normal operation. To generate only the voltage drop of0.066V or less, the resistance between the adjacent branch points of theauxiliary electrode connected to the conductive unit in which the shortcircuit occurs is desired to be 35Ω or less. Alternatively, the voltagedrop may also be reduced by increasing a width of the auxiliaryelectrode or by introducing another branch point before the distancebetween the branch points exceeds 21 mm for additionally distributingthe current.

According to an exemplary embodiment of the present specification, in acase in which the OLED is short-circuited, the voltage drop is desiredto be 0.033V or less in order to achieve the luminance non-uniformitywithin 5% of the normal operation. To generate only the voltage drop of0.033V or less, the resistance between the adjacent branch points of theauxiliary electrode connected to the conductive unit in which the shortcircuit occurs is desired to be 18Ω or less. Alternatively, the voltagedrop may also be reduced by increasing a width of the auxiliaryelectrode or by introducing another branch point before the distancebetween the branch points exceeds 10 mm for additionally distributingthe current.

According to an exemplary embodiment of the present specification, thesurface resistance of the auxiliary electrode may be 3Ω/□ or less.Specifically, the surface resistance may be 1Ω/□ or less.

In a case in which any one surface resistance of the first electrode andthe second electrode having a wide area is higher than a desired level,voltage may vary for each position of the electrode. Accordingly, when apotential difference between the first electrode and the secondelectrode disposed based on the organic layer varies, the luminanceuniformity of the OLED may be degraded. Accordingly, in order todecrease the surface resistance of the first electrode or the secondelectrode that is higher than the desired level, the auxiliary electrodemay be used. The surface resistance of the auxiliary electrode may be3Ω/□ or less, and specifically, may be 1Ω/□ or less. In the above range,the luminance uniformity of the OLED may be maintained at a high level.

According to an exemplary embodiment of the present specification, thefirst electrode may be formed as a transparent electrode. In this case,the surface resistance of the first electrode may be higher than asurface resistance value suitable for driving the OLED. Accordingly, todecrease the surface resistance value of the first electrode, thesurface resistance of the first electrode may be reduced to a surfaceresistance level of the auxiliary electrode by electrically connectingthe auxiliary electrode and the first electrode.

According to an exemplary embodiment of the present specification, theauxiliary electrode may be provided on an area excluding a lightemitting area. Specifically, the auxiliary electrode may be provided onthe current carrying portion of the first electrode. Alternatively, in acase in which the current carrying portion of the first electrode isabsent, the auxiliary electrode may be provided on an area in which thecurrent carrying portion of the first electrode is to be positioned.

According to an exemplary embodiment of the present specification, theauxiliary electrode may include conductive lines that are electricallyconnected to each other. Specifically, the conductive lines may includeconductive units. Specifically, it may be possible to drive an entireauxiliary electrode by applying a voltage to at least a portion of theauxiliary electrode.

According to an exemplary embodiment of the present specification, theOLED may be included in an OLED lighting and thereby used. In the caseof the OLED light, it may be desirable to emit light having a uniformbrightness from an entire light emitting area, that is, all of theOLEDs. Specifically, to achieve a uniform brightness in the OLEDlighting, a voltage between the first electrode and the second electrodeof each of all the OLEDs included in the OLED lighting may be maintainedto be constant.

In a case in which the first electrode is a transparent electrode andthe second electrode is a metal electrode, a surface resistance of thesecond electrode of each OLED is sufficiently low and thus, a voltagedifference of the second electrode of each OLED barely exists. However,in the case of the first electrode, a voltage difference of each OLEDmay be present. According to an exemplary embodiment of the presentspecification, the auxiliary electrode, specifically, a metal auxiliaryelectrode may be used to compensate for such a voltage difference of thefirst electrode of each OLED. Further, the metal auxiliary electrode mayinclude conductive lines that are electrically connected to each other,thereby enabling the voltage difference of the first electrode of eachOLED to barely exist.

According to an exemplary embodiment of the present specification, theOLED may include a short-circuit preventing layer provided between thefirst electrode and the auxiliary electrode, and the auxiliary electrodemay be electrically connected to the conductive unit through theshort-circuit preventing layer. That is, the auxiliary electrode may beelectrically connected to the conductive unit through the short-circuitpreventing layer. The short-circuit preventing layer may perform ashort-circuit preventing function of the OLED.

According to an exemplary embodiment of the present specification, theshort-circuit preventing layer may be provided on at least one surfaceof the auxiliary electrode in contact therewith. Specifically, accordingto an exemplary embodiment of the present specification, theshort-circuit preventing layer may be provided on a top surface, abottom surface, or a side surface on which the auxiliary electrode isformed.

The short-circuit preventing layer may be applied together with theconductive connector and thereby perform a short-circuit preventingfunction of the OLED. Also, even when the conductive connector isabsent, the short-circuit preventing layer alone may perform ashort-circuit preventing function of the OLED.

The short-circuit preventing layer may be provided on the currentcarrying portion of the first electrode. Alternatively, when the firstelectrode includes only at least two conductive units, the short-circuitpreventing layer may be provided to contact with one area of theconductive units.

According to an exemplary embodiment of the present specification, dueto an increase in resistance resulting from the short-circuit preventinglayer, the resistance between the auxiliary electrode and the conductiveunit electrically connected through the short-circuit preventing layermay be 1,000Ω or more and 300,000Ω or less. According to an exemplaryembodiment of the present specification, resistance from the auxiliaryelectrode of the short-circuit preventing layer to the first electrodemay be 1,000Ω or more and 300,000Ω or less. Specifically, the resistancefrom the auxiliary electrode of the short-circuit preventing layer tothe first electrode may be resistance from the auxiliary electrode toany one conductive connector.

According to an exemplary embodiment of the present specification, thethickness of the short-circuit preventing layer may be 1 nm or more and10 μm or less.

The short-circuit preventing layer within the thickness range and/or thethickness direction resistance range may maintain normal operatingvoltage in a case in which the short circuit does not occur in the OLED.Also, even though the short circuit occurs in the OLED within thethickness range and/or the resistance range, the OLED may operate withinthe normal range.

Specifically, according to an exemplary embodiment of the presentspecification, resistance of the short-circuit preventing layerindicates resistance from the auxiliary electrode to the conductiveconnector or the conductive unit. Alternatively, according to anexemplary embodiment of the present specification, the resistance of theshort-circuit preventing layer indicates resistance from the auxiliaryelectrode to the current carrying portion of the first electrode. Thatis, the resistance of the short-circuit preventing layer indicatesresistance according to an electrical distance for electrical connectionfrom the auxiliary electrode to the conductive connector or theconductive unit.

According to an exemplary embodiment of the present specification, thevolume resistivity (ρ_(slp)) (Ωcm) of the short-circuit preventing layermay be calculated according to the following formula.

$\rho_{spl} = \frac{R_{{cell} - {spl}} \times A_{spl}}{t_{spl}}$

A_(spl)(cm²) denotes an area in which electricity may flow in athickness direction from the auxiliary electrode formed on oneconductive unit to one conductive unit through the short-circuitpreventing layer. That is, A_(spl)(cm²) denotes an area overlapping anarea of the auxiliary electrode formed on the short-circuit preventinglayer in an area of the short-circuit preventing layer formed on onefirst electrode.

R_(cell-spl) denotes resistance (Ω) of the short-circuit preventingportion in one conductive unit.

t_(slp)(μm) may denote a thickness of the short-circuit preventinglayer. Alternatively, t_(slp)(μm) may denote the shortest distance inwhich electricity moves from the auxiliary electrode to the conductiveconnector or the conductive unit.

The thickness direction exemplifies an example in which the electricitymoves in the short-circuit preventing layer and indicates a direction inwhich the electricity moves from one area of the short-circuitpreventing layer to another area thereof.

Specifically, A_(spl)(cm²) may denote an area of the short-circuitpreventing layer simultaneously overlapping the first electrode formedthereon and the auxiliary electrode formed therebelow in a case in whichthe short-circuit preventing layer is positioned between the firstelectrode and the auxiliary electrode. As an example, in a case in whichthe entire bottom surface of the short-circuit preventing layer isformed on the first electrode in contact therewith and the auxiliaryelectrode is formed on the entire top surface of the short-circuitpreventing layer in contact therewith, A_(spl)(cm²) may be an area ofthe short-circuit preventing layer overlapping the first electrode. Asanother example, in a case in which the entire bottom surface of theshort-circuit preventing layer is formed on the first electrode incontact therewith and the auxiliary electrode is formed on a portion ofthe top surface of the short-circuit preventing layer, A_(spl)(cm²) maybe an area of the short-circuit preventing layer simultaneouslyoverlapping the first electrode and the auxiliary electrode.

As it can be known from the above formula, the volume resistivity(ρ_(slp)) of the short-circuit preventing layer formed on one conductiveunit may be determined based on the thickness direction resistance(R_(cell-spl)) of the short-circuit preventing layer in one conductiveunit, the area (A_(spl)) in which the electricity may flow in thethickness direction from the auxiliary electrode formed on oneconductive unit to one conductive unit through the short-circuitpreventing layer, and the thickness (t_(slp)) of the short-circuitpreventing layer.

According to an exemplary embodiment of the present specification, thevolume resistivity of the short-circuit preventing layer may be 9 Ωcm ormore and 8.1×10¹⁰ Ωcm or less. Within the above range, the short-circuitpreventing layer may maintain normal operating voltage in a case inwhich the short-circuit does not occur in the OLED. Also, theshort-circuit preventing layer may perform a short-circuit preventingfunction. Even through the short circuit occurs, the OLED may operatewithin the normal range. The volume resistivity may be calculated asfollows.

According to an exemplary embodiment of the present specification, in acase in which a range of the resistance of the short-circuit preventinglayer is 1,000Ω or more and 300,000Ω or less, the thickness of theshort-circuit preventing layer is 1 nm or more and 10 μm or less, and anarea of one cell is 300×300 μm² to 3×3 mm², the area (A_(spl)) in whichthe electricity may flow in the thickness direction from the auxiliaryelectrode formed on one cell to the first electrode of one cell throughthe short-circuit preventing layer may be determined within the range of1% to 30% of the area of one cell. Accordingly, the area (A_(spl)) inwhich the electricity may flow in the thickness direction from theauxiliary electrode formed on one cell to the first electrode of onecell through the short-circuit preventing layer may be 9×10⁻⁶ cm² (300μm×300 μm×0.01) to 2.7×10⁻² cm² (0.3 cm×0.3 cm×0.3). In this case, thevolume resistivity of the short-circuit preventing layer may becalculated according to the following formula.

$\frac{1,000\mspace{14mu}\Omega \times 9 \times 10^{- 6}\mspace{14mu}{cm}^{2}}{10\mspace{14mu}{\mu m}} \leq \rho_{spl} \leq \frac{300,000\mspace{14mu}\Omega \times 2.7 \times 10^{- 2}\mspace{14mu}{cm}^{2}}{0.001\mspace{14mu}{\mu m}}$

According to an exemplary embodiment of the present specification, theshort-circuit preventing layer may include one or more selected from agroup including carbon powder; carbon film; conductive polymer; organicpolymer; metal; metal oxide; inorganic oxide; metal sulfide; andinsulating material. Specifically, a mixture of at least two selectedfrom zirconium oxide (ZrO₂), nichrome, indium tin oxide (ITO), zincsulfide (ZnS), and silicon dioxide (SiO₂) may be used.

According to an exemplary embodiment of the present specification, thesurface resistance of the conductive unit may be 1Ω/□ or more, or may be3Ω/□ or more, and particularly, may be 10Ω/□ or more. Also, the surfaceresistance of the conductive unit may be 10,000Ω/□ or less, or may be1,000Ω/□ or less. That is, the surface resistance of the conductive unitmay be 1Ω/□ or more and 10,000Ω/□ or less, or may be 10Ω/□ or more and1,000Ω/□ or less.

The conductive unit and the conductive connector may be formed bypatterning the first electrode and thus, the surface resistance of theconductive unit may be identical to the surface resistance of the firstelectrode or the conductive connector.

According to an exemplary embodiment of the present specification, asurface resistance level suitable for the conductive unit may becontrolled to be in an inverse proportion to an area of the conductiveunit corresponding to a light emitting area. For example, when theconductive unit has a light emitting area corresponding to an area of100 cm², the surface resistance suitable for the conductive unit may bearound 1Ω/□. Further, in the case of forming an area of each conductiveunit to be small, the surface resistance suitable for the conductiveunit may be 1Ω/□ or more.

The surface resistance of the conductive unit may be determined based ona material for forming the conductive unit, and may also be decreased toa surface resistance level of the auxiliary electrode through beingelectrically connected to the auxiliary electrode. Accordingly, asurface resistance value of the conductive unit suitable for the OLEDmay be adjusted based on a material of the auxiliary electrode and theconductive unit.

According to an exemplary embodiment of the present specification, thefirst electrode may include 1,000 or more conductive units separate fromeach other. Specifically, the first electrode may include 1,000 or moreand 1,000,000 or less conductive units separate from each other.

Also, according to an exemplary embodiment of the present specification,the first electrode may be formed in a pattern of at least twoconductive units. Specifically, the conductive unit may be formed in apattern in which areas excluding the conductive connector are separatefrom each other.

The pattern of the conductive unit may have a shape of a closed figure.Specifically, the pattern may be provided in a polygonal shape, such asa triangular shape, a rectangular shape, and a hexagonal shape, and maybe provided in an amorphous shape.

When the number of conductive units is 1,000 or more, it may be possibleto reduce or minimize a leakage current amount in the case of theshort-circuit occurrence while reducing or minimizing a voltage increaselevel in the case of the normal operation of the OLED. Also, as thenumber of conductive units increases up to 1,000,000, the above effectsmay be maintained while maintaining an aperture ratio. That is, when thenumber of conductive units exceeds 1,000,000, the aperture ratio may bedegraded due to an increase in the number of auxiliary electrodes.

According to an exemplary embodiment of the present specification, anoccupying area of the conductive units in the OLED may be 50% or moreand 90% or less based on a top view of an entire OLED. Specifically, theconductive unit is included in the light emitting area and the occupyingarea of the conductive units based on a surface on which the entire OLEDemits light may be the same as or similar to an aperture ratio of theOLED.

In the case of the first electrode, the respective conductive units areelectrically connected by the conductive connector and/or theshort-circuit preventing layer and thus, driving voltage of the OLEDincreases. Therefore, according to an exemplary embodiment of thepresent specification, the first electrode includes 1,000 or moreconductive units to supplement an increase in the driving voltage by theconductive connector. As a result, it may be possible to decrease thedriving voltage of the OLED and at the same time, to enable the firstelectrode to have a short-circuit preventing function by the conductiveconnector.

According to an exemplary embodiment of the present specification, anarea of each conductive unit may be 0.01 mm² or more and 25 mm² or less.

In the case of reducing the area of each conductive unit, it may bepossible to simultaneously decrease an operating voltage increase rateaccording to the conductive connector introduced for short-circuitprevention and a value of operating current to leakage current. Also, ina case in which a non-emitting conductive unit is present due to theoccurrence of short circuit, it may be possible to minimize a decreasein the product quality by minimizing the non-emitting area. Here, in thecase of significantly reducing the area of the conductive unit, a ratioof the emitting area in the OLED may significantly decrease and thus,the efficiency of the OLED may be degraded due to a decrease in theaperture ratio. Accordingly, in the case of manufacturing the OLED usingthe area of the conductive unit, it may be possible to reduce orminimize the aforementioned disadvantages, while maintaining theaforementioned advantages.

According to the OLED according to an exemplary embodiment of thepresent specification, the short-circuit preventing portion, theconductive unit, and the organic layer including the light emittinglayer may be electrically connected in series to each other. The lightemitting layer may be positioned between the first electrode and thesecond electrode. Each of at least two light emitting layers may beelectrically connected in parallel.

According to an exemplary embodiment of the present specification, thelight emitting layer may be positioned between the conductive unit andthe second electrode, and each light emitting layer may be electricallyconnected in parallel to each other. That is, the light emitting layermay be positioned to correspond to an area corresponding to theconductive unit.

In a case in which the light emitting layer operates in the same currentdensity, a resistance value increases in inverse proportion to adecrease in an area of the light emitting layer. According to anexemplary embodiment of the present specification, in a case in which anarea of each conductive unit decreases and the number of conductiveunits increases, an area of each light emitting layer also decreases. Inthis case, in a case in which the OLED operates, a ratio of voltage ofthe conductive connectors connected in series to the organic layerdecreases compared to voltage applied to the organic layer including thelight emitting layer.

In a case in which a short circuit occurs in the OLED according to anexemplary embodiment of the present specification, a leakage currentamount may be determined based on a resistance value from the auxiliaryelectrode to the conductive unit and operating voltage, regardless ofthe number of conductive units. Accordingly, when increasing the numberof conductive units, it may be possible to reduce or minimize a voltageincrease phenomenon by the conductive connector in the case of thenormal operation, while reducing or minimizing a leakage current amountin the case of the short-circuit occurrence.

According to an exemplary embodiment of the present specification, theOLED may further include a substrate and the first electrode may beprovided on the substrate.

According to an exemplary embodiment of the present specification, thefirst electrode may be a transparent electrode.

When the first electrode is the transparent electrode, the firstelectrode may be manufactured using conductive oxide such as indium tinoxide (ITO) or indium zinc oxide (IZO). Further, the first electrode mayalso be a translucent electrode. When the first electrode is thetranslucent electrode, the first electrode may be manufactured using atranslucent metal such as Ag, Au, Mg, Ca, or the alloy thereof. When thetranslucent metal is used for the first electrode, the OLED may have amicro-cavity structure.

According to an exemplary embodiment of the present specification, theauxiliary electrode may be formed of a metal material. That is, theauxiliary electrode may be a metal electrode.

The auxiliary electrode may be formed of any type of metals.Specifically, the metals may include aluminum, copper, and/or silverhaving an excellent conductivity. In the case of using aluminum forstability during an adhesive power and photolithography process with atransparent electrode, the auxiliary electrode may also use a layer ofmolybdenum/aluminum/molybdenum.

According to an exemplary embodiment of the present specification, theorganic layer may include at least one light emitting layer and mayfurther include one or more selected from a group including a holeinjecting layer; a hole transporting layer; a hole preventing layer; acharge generating layer; an electron preventing layer; an electrontransporting layer; and an electron injecting layer.

The charge generating layer refers to a layer in which holes andelectrons are generated when a voltage is applied thereto.

The substrate may use a substrate having a good transparency, surfacesmoothness, easy handling and waterproof. Specifically, the substratemay use a glass substrate, a thin film glass substrate or a transparentplastic substrate. A film, such as polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyether ether ketone (PEEK), andpolyimide (PI), may be included in the plastic substrate in a form of asingle layer or a plurality of layers. Also, the substrate mayautonomously include a light scattering function. Here, the substrate isnot limited thereto and may use a substrate generally used for the OLED.

According to an exemplary embodiment of the present specification, thefirst electrode may be an anode and the second electrode may be acathode. Also, the first electrode may be the cathode and the secondelectrode may be the anode.

A material having a high work function may be used for the anode so thathole injection into the organic layer may be smoothly performed.Specific examples of an anode material may include a metal such asvanadium, chrome, copper, zinc, and gold, or the alloy thereof; metaloxide such as zinc oxide, indium oxide, indium tin oxide (ITO), andindium zinc oxide (IZO); a combination of a metal and oxide such asZnO:Al or SnO₂:Sb; conductive polymer such as poly(3-methylthophene),poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole, andpolyaniline, and the like, but are not limited thereto.

The anode material is not limited only to the anode and may be used as amaterial of the cathode.

A material having a low work function may be used for the cathode sothat electron injection into the organic layer may be smoothlyperformed. Specific example of a cathode material may include a metalsuch as magnesium, calcium, sodium, potassium, titanium, indium,yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or thealloy thereof; a multi-structured material such as LiF/Al or LiO₂/Al,and the like, but are not limited thereto.

The cathode material is not limited only to the cathode and may be usedas a material of the anode.

A material having a high mobility with respect to holes may be suitablefor a material of the hole transporting layer according to an exemplaryembodiment of the present specification, which is a material capable ofreceiving a hole from the anode or the hole injecting layer andtransporting the hole to the light emitting layer. Specific examplesthereof may include an arylamine-based organic material, conductivepolymer, and block copolymer in which a conjugate portion and anon-conjugate portion are present together, but are limited thereto.

A material having a high quantum efficiency with respect to fluorescenceor phosphorescence may be suitable for a material of the light emittinglayer according to an exemplary embodiment of the present specification,which is a material capable of emitting light of a visible area byreceiving holes and electrons from the hole transporting layer and theelectron transporting layer, respectively, and thereby combining theholes and the electrons. Specific examples thereof may include8-hydroxy-quinoline aluminum complex (Alq₃); carbazole-based compound;dimerized styryl compound; BAlq; 10-hydroxy benzoquinoline-metalcompound; benzoxazole, benzthiazole and bezimidazole-based compound;poly(p-phenylenevinylene) (PPV) based polymer; spiro compound;polyfluorrene; rubrenes, and the like, but are not limited thereto.

A material having a high mobility with respect to electrons may besuitable for a material of the electron transporting layer according toan exemplary embodiment of the present specification, which is amaterial capable of receiving electrons injected from the cathode andtransporting the electrons to the light emitting layer. Specificexamples thereof may include Al complex of 8-hydroxyquinoline; complexincluding Alq₃; organic radical compound; hydroxyflavone-metal complex,and the like, but are not limited thereto.

According to an exemplary embodiment of the present specification, theauxiliary electrode may be positioned on a non-emitting area of theOLED.

According to an exemplary embodiment of the present specification, theOLED may further include an insulating layer provided on thenon-emitting area.

According to an exemplary embodiment of the present specification, theinsulating layer may insulate the short-circuit preventing portion andthe auxiliary electrode from the organic layer.

According to an exemplary embodiment of the present specification, theOLED may be sealed with an encapsulating layer.

The encapsulating layer may be formed as a transparent resin layer. Theencapsulating layer may function to protect the OLED from oxygen andpollutant materials and may be formed of a transparent material in ordernot to degrade the luminescence of the OLED. The transparency indicatestransmitting 60% or more of light. Specifically, the transparencyindicates transmitting 75% or more of light.

According to an exemplary embodiment of the present specification, theOLED may further include a light scattering layer. Specifically,according to an exemplary embodiment of the present specification, theOLED may further include a substrate on a surface facing a surface onwhich the organic layer of the first electrode is provided, and mayfurther include the light scattering layer provided between thesubstrate and the first electrode. According to an exemplary embodimentof the present specification, the light scattering layer may include aflattening layer. According to an exemplary embodiment of the presentspecification, the flattening layer may be provided between the firstelectrode and the light scattering layer.

Alternatively, according to an exemplary embodiment of the presentspecification, the OLED may further include a substrate on the surfacefacing the surface on which the organic layer of the first electrode isprovided, and may further include a light scattering layer provided on asurface facing a surface on which the first electrode of the substrateis provided.

According to an exemplary embodiment of the present specification, ifthe light scattering layer is provided in a structure capable ofimproving a light extraction efficiency of the OLED by inducing lightscattering, the light scattering layer is not particularly limited.Specifically, according to an exemplary embodiment of the presentspecification, the light scattering layer may be provided in a structurein which scattering particles are distributed within a binder, a filmhaving an unevenness, and/or a film having haziness.

According to an exemplary embodiment of the present specification, thelight scattering light may be directly formed on the substrate using amethod such as spin coating, bar coating, and slit coating, or may beformed using a method of manufacturing the light scattering layer in afilm form and thereby attaching the same.

According to an exemplary embodiment of the present specification, theOLED may be a flexible OLED. In this case, the substrate may include aflexible material. Specifically, the substrate may be a bendablethin-film glass substrate, a plastic substrate, or a film typesubstrate.

A material of the plastic substrate is not particularly limited, but maygenerally include a film, such as polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyether ether ketone (PEEK), andpolyimide (PI), in a form of a single layer or a plurality of layers.

An exemplary embodiment of the present specification provides a displaydevice including an OLED. In the display device, the OLED may functionas a pixel or a backlight. In addition, various configurations known inthe art can be applied to the display device.

An exemplary embodiment of the present specification provides a lightingdevice including an OLED. In the lighting device, the OLED may functionas a light emitter. In addition, various configurations known in the artmay be applied to the lighting device.

An exemplary embodiment of the present specification provides a methodfor manufacturing the OLED. Specifically, the exemplary embodiment ofthe present specification provides the method for manufacturing theOLED, the method including preparing a substrate; forming a firstelectrode including at least two conductive units on the substrate;forming an auxiliary electrode disposed to be separate from theconductive units and at least two branch points each having at leastthree branches; forming at least one organic layer on the firstelectrode; and forming a second electrode on the organic layer.

According to an exemplary embodiment of the present specification, theforming of the first electrode may form the first electrode to includeat least two conductive units and a conductive connector connected toeach conductive unit.

According to an exemplary embodiment of the present specification, theforming of the auxiliary electrode may form the auxiliary electrode onone end portion of each conductive connector.

According to an exemplary embodiment of the present specification, themethod for manufacturing the OLED may further include forming ashort-circuit preventing layer to be provided between the firstelectrode and the auxiliary electrode during a period between theforming of the first electrode and the forming of the auxiliaryelectrode.

According to an exemplary embodiment of the present specification, theOLED may emit a white light having a color temperature of 2,000 K ormore and 12,000 K or less.

Hereinafter, Examples will be described in detail to specificallydescribe embodiments of the present specification. However, theseExamples can be modified in various different forms or configurationsand thus, should not be interpreted in limiting the scope of the presentspecification.

EXAMPLE

A light emitting area was manufactured to be 40×40 mm² by forming thefirst electrode on the substrate using ITO. Here, the surface resistanceof ITO was 10Ω/□. The auxiliary electrode was formed to be in a meshform of surrounding the light emitting area with a width of 20 μm and athickness of 500 nm using copper (Cu). Also, an interval of theauxiliary electrode was manufactured to be about 0.82 mm. Also, theconductive connector was manufactured to have a length of 1560 μm, awidth of 20 μm, and resistance of 780Ω or more. Also, an area of eachconductive unit was manufactured to be 0.56 mm². The number ofconductive units included in the manufactured OLED was 49×49 (2410conductive units). In the manufactured OLED, aside from an ITO areacorresponding to the light emitting area, an area in which a metalauxiliary electrode is exposed and an area in which ITO is patterned andthereby removed were insulated using a photosensitive insulatingmaterial.

A white OLED having the light emitting area of 40×40 mm² wasmanufactured by sequentially stacking the organic layer including thelight emitting layer and the second electrode.

Aluminum (Al) was used for the second electrode, and the organic layerwas formed in a structure of including a hole injecting layer, a holetransporting layer, an organic light emitting layer, an electrontransporting layer, and an electron injecting layer. The organic lightemitting layer was formed in a double-layered structure including a bluelight emitting layer using a fluorescent material and a green and redlight emitting layer using a phosphorescent material. The material usedfor each stack structure has used a material generally used in amanufacturing field of the white OLED. The manufacturing method has alsoused a generally used method.

Comparative Example

Except for that the auxiliary electrode was formed to be in parallelwith a line width of 20 μm and the auxiliary electrode connected in aparallel form with a metal line formed on an outer edge area of 40 mm×40mm was formed in a striped shape, the white OLED was manufactured basedon the same conditions as Example 1.

FIG. 8 illustrates a partial area of a state in which a first electrodeand an auxiliary electrode are formed during a manufacturing process ofan OLED manufactured according to an Example of the presentspecification and a Comparative Example. In FIG. 8, the auxiliaryelectrode of the OLED (e) manufactured according to the ComparativeExample was formed in a stripe shape, and the auxiliary electrode of theOLED (f) manufactured according to the Example was formed in a meshshape.

FIG. 9 illustrates a state after causing a short-circuit defect to anOLED manufactured according to the Example and the Comparative Example.Referring to FIG. 9, it can be observed from the OLED (g) manufacturedaccording to the Comparative Example that luminescence intensity isdecreased in a portion around a short-circuit occurrence area due to avoltage drop (IR drop) phenomenon. On the contrary thereto, it can beverified from the OLED (h) manufactured according to the Example thatluminescence does not occur only in the short-circuit occurrence areaand the luminescence intensity is not degraded in the portion around theshort-circuit occurrence area.

In the case of the OLED manufactured according to the ComparativeExample, the efficiency was a level of 60 lm/W. Operating voltage was 6V and operating current density was about 3 mA/cm². The conductive unitwas connected to one metal auxiliary electrode having the line width of20 μm at an interval of about 850 μm. The number of conductive units was49×49 (2401 conductive units). Further, in a state in which theshort-circuit defect is not generated, an amount of current flowing fromone conductive unit through the second electrode may be calculated to be(4 cm×4 cm×3 mA/cm²)/2401=0.02 mA. In the OLED manufactured according tothe Comparative Example, the auxiliary electrode was formed to have awidth of 20 μm, a thickness of 500 nm, and a length of 40 nm using Cu.Resistance of both ends of the auxiliary electrode was 67Ω.

FIG. 10 shows potential of an auxiliary electrode per position in a casein which a short circuit defect has not occurred in an OLED according toa Comparative Example. That is, FIG. 10 shows voltage of the auxiliaryelectrode per position of the conductive unit in a case in which theshort circuit has not occurred, current for operation of the OLEDaccording to the Comparative Example was injected into only both ends ofthe auxiliary electrode and flew into the organic layer and the secondelectrode through each conductive unit connected to the auxiliaryelectrode.

Referring to FIG. 10, a position at which the maximum voltage drop hasoccurred in the auxiliary electrode was a center point of the OLED thatis farthest away from an edge point of the auxiliary electrode, and thevoltage drop at the center point of the OLED was about 0.009 V.

In a case in which the short-circuit defect has occurred in the 25^(th)conductive unit from the edge point of the OLED according to theComparative Example, when the operating voltage is 6V and resistance ofthe conductive connector connected to the conductive unit in which theshort circuit has occurred is 780Ω, an amount of leakage current was 7.7mA (6 V/780Ω).

FIG. 11 shows potential of an auxiliary electrode per position in a casein which a short circuit has occurred in an OLED according to theComparative Example.

Referring to FIG. 11, in a case in which the short circuit has occurredin the OLED according to the Comparative Example, the voltage drop wasabout 0.13V and thus, voltage drop of about 10 folds compared to anormal operation has occurred. Accordingly, in a short-circuitoccurrence area, voltage of the first electrode and voltage of thesecond electrode have a value lower by about 0.13V than 6V that is inputvoltage. Accordingly, an amount of current flowing in the organic layerformed around the short-circuit occurrence area also decreases, whichresults in decreasing luminescence intensity.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. An organic light emitting device (OLED),comprising: a first electrode including at least two conductive unitsthat are immediately adjacent to each other; a second electrode facingthe first electrode; an organic layer between the first electrode andthe second electrode; an auxiliary electrode electrically connected tothe first electrode, the auxiliary electrode including at least twobranch points that are immediately adjacent to each other, each branchpoint having at least three branches; and a short-circuit preventingportion between the at least two conductive units and the auxiliaryelectrode, wherein the at least two conductive units and the auxiliaryelectrode are electrically connected through each of the short-circuitpreventing portion, wherein a resistance between the at least two branchpoints is 35Ω or less, and wherein a resistance between the at least twoconductive units is 2,000Ω or more and 600,000Ω or less.
 2. The OLEDaccording to claim 1, wherein the auxiliary electrode has a meshstructure surrounding each of the at least two conductive units.
 3. TheOLED according to claim 1, wherein a distance between the at least twobranch points of the auxiliary electrode is 21 mm or less.
 4. The OLEDaccording to claim 1, wherein a distance between the at least two branchpoints of the auxiliary electrode is 10 mm or less, and wherein aresistance between the at least two branch points of the auxiliaryelectrode is 18Ω or less.
 5. The OLED according to claim 1, wherein eachconductive unit is electrically connected to the auxiliary electrode inparallel.
 6. The OLED according to claim 1, wherein the short-circuitpreventing portion includes a conductive connector, a short-circuitpreventing layer, or the conductive connector and the short-circuitpreventing layer.
 7. The OLED according to claim 1, wherein at a currentdensity of any one value of 1 mA/cm² to 5 mA/cm², the short-circuitpreventing portion has a resistance value at which an operating voltageincrease rate of the following Formula 1 and a numerical value ofoperating current to leakage current of the following Formula 2simultaneously satisfy 0.03 or less: $\begin{matrix}\frac{V_{t} - V_{o}}{V_{o}} & \left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack \\\frac{I_{s}}{I_{t}} & \left\lbrack {{Formula}\mspace{14mu} 2} \right\rbrack\end{matrix}$ wherein V_(t)(V) denotes an operating voltage of the OLEDto which the short-circuit preventing portion is applied and in which ashort circuit defect is absent, V_(o)(V) denotes an operating voltage ofthe OLED to which the short-circuit preventing portion is not appliedand in which the short-circuit defect is absent, I_(t)(mA) denotes anoperating current of the OLED to which the short-circuit preventingportion is applied and in which the short-circuit defect is absent, andI_(s)(mA) denotes a leakage current of the OLED to which theshort-circuit preventing portion is applied and in which theshort-circuit defect is present in any one conductive unit.
 8. The OLEDaccording to claim 1, wherein a resistance from each conductive unit tothe auxiliary electrode is 1,000Ω or more and 300,000Ω or less.
 9. TheOLED according to claim 1, wherein the first electrode furtherincludes-at least two conductive connectors each including an area inwhich a length of a direction in which current substantially flows islonger than a width of a vertical direction thereof, and one end portionof each conductive connector is electrically connected to one of the atleast two conductive units, and another end portion thereof iselectrically connected to the auxiliary electrode.
 10. The OLEDaccording to claim 9, wherein the auxiliary electrode is disposed to beseparated from the at least two conductive units; and an area excludingthe end portion of the each conductive connector in contact with theauxiliary electrode.
 11. The OLED according to claim 9, wherein eachconductive connector includes an area in which a ratio of the length tothe width is about 10:1 or more.
 12. The OLED according to claim 9,wherein resistance of each conductive connector satisfies the followingFormula 3:(length of conductive connector ÷ width of conductive connector) xsurface resistance of conductive connector ≧1,000Ω  [Formula 3].
 13. TheOLED according to claim 9, wherein the first electrode further includesa current carrying portion of the first electrode electrically connectedto the conductive connectors, and the auxiliary electrode iselectrically connected to the conductive connectors through the currentcarrying portion of the first electrode.
 14. The OLED according to claim6, wherein the short-circuit preventing portion includes theshort-circuit preventing layer, which is provided on at least a onesurface of the auxiliary electrode in contact therewith.
 15. The OLEDaccording to claim 6, wherein the short-circuit preventing portionincludes the short-circuit preventing layer, which is provided on a topsurface, a bottom surface, or a side surface on which the auxiliaryelectrode is formed.
 16. The OLED according to claim 6, wherein theshort-circuit preventing portion includes the short-circuit preventinglayer, and wherein a thickness of the short-circuit preventing layer is1 nm or more and 10 μm or less.
 17. The OLED according to claim 6,wherein the short-circuit preventing portion includes the short-circuitpreventing layer, and wherein a volume resistivity of the short-circuitpreventing layer is 9 Ωcm or more and 8.1 ×10¹⁰ Ωcm or less.
 18. TheOLED according to claim 6, wherein the short-circuit preventing portionincludes the short-circuit preventing layer, and wherein theshort-circuit preventing layer includes one or more selected from agroup consisting of a carbon powder; a carbon film; a conductivepolymer; an organic polymer; a metal; a metal oxide; an inorganic oxide;a metal sulfide; and an insulating material.
 19. The OLED according toclaim 1, further comprising: a substrate, wherein the first electrode isprovided on the substrate.
 20. The OLED according to claim 1, wherein asurface resistance of each conductive unit is 1Ω/□ or more.
 21. The OLEDaccording to claim 1, wherein the first electrode has 1,000 or moreconductive units separated from each other.
 22. The OLED according toclaim 1, wherein a surface resistance of the auxiliary electrode is 3Ω/□or less.
 23. The OLED according to claim 1, wherein the first electrodeis a transparent electrode.
 24. The OLED according to claim 1, whereinthe auxiliary electrode is a metal electrode.
 25. The OLED according toclaim 1, wherein the organic layer further includes at least one lightemitting layer and further includes one or more selected from a groupconsisting of a hole injecting layer; a hole transporting layer; a holepreventing layer; a charge generating layer; an electron preventinglayer; an electron transporting layer; and an electron injecting layer.26. The OLED according to claim 1, wherein the auxiliary electrode ispositioned on a non-emitting area of the OLED.
 27. The OLED according toclaim 1, wherein the OLED emits a white light having a color temperatureof 2,000 K or more and 12,000 K or less.
 28. The OLED according to claim1, further comprising: a substrate provided on a surface facing asurface on which an organic layer of the first electrode is provided;and a light scattering layer provided between the substrate and thefirst electrode.
 29. The OLED according to claim 28, wherein the lightscattering layer includes a flattening layer.
 30. The OLED according toclaim 1, further comprising: a substrate provided on a surface facing asurface on which an organic layer of the first electrode is provided;and a light scattering layer provided on a surface facing a surface onwhich the first electrode of the substrate is provided.
 31. The OLEDaccording to claim 1, wherein the OLED is a flexible OLED.
 32. The OLEDaccording to claim 1, wherein the OLED is a display device or a lightingdevice.
 33. A method for manufacturing an organic light emitting device(OLED), the method comprising: forming a first electrode including atleast two conductive units on a substrate; forming an auxiliaryelectrode that is separate from the at least two conductive units andincludes at least two branch points, each branch point having at leastthree branches; forming an organic layer on the first electrode; andforming a second electrode on the organic layer, wherein the methodfurther comprises forming a short-circuit preventing layer between thefirst electrode and the auxiliary electrode during a period between theforming of the first electrode and the forming of the auxiliaryelectrode.
 34. The method according to claim 33, wherein the forming ofthe first electrode forms the first electrode that includes the at leasttwo conductive units and a conductive connector connected to eachconductive unit.